Towed glider



y 6 0 R. M. CARLSON 2,507,957

TOWED GLIDER Filed June 15, 1946 3 Sheets-Sheet 1 INVENTOR.

. v RusseLL M. Carlson.

ATTORNEY y 1950 R. M. CARLSON 2,507,957

TOWED GLIDER 5 Sheets-Sheet 2 Filed June 15, 1946 g 88 I /04 g }/o l A/06 m3 5 :Wdx.

B l l Fig. 3

Fig. 2 INVENTOR.

RUSSElL M- Carlson BY -QGMM ATTORNEY May 16, 1950 R. M. CARLSON TOWEDGLIDER 3 Sheets-Sheet 55 Filed June 15, 1946 INVEN TOR. Russell M.Carlson. BY

67?]. 63, Wuluu ATmRNEY Patented May 16, 1950 UNITED STATES ATENT OFFICETOWED GLIDER Application June 15, 1946, Serial No. 676,989

19 Claims.

This invention relates to a towed winged target adapted to be utilizedfor anti-aircraft and fighter practice and other towed gliders such ascargo gliders.

A \principal object of the invention is to provide a high speed glidertarget which can be towed in an offset position relative to the towingplane during target practice and which can be towed in an in-lineposition during take oif and landing of the target. Similarly, othergliders, such as cargo gliders, may be towed in substantially an in-lineposition during take off and landing and in an offset position duringflight, especially where two or more gliders are to be towed.

Another object of the invention i the provision of means for controllingthe movement of the towed glider between its in-line and off'setpositions.

A further object of the invention is the provision of improved mechanismcarried .by the glider for shifting the glider from its off-set to itsin-line relation, or the reverse, which is responsive to the will of thepilot in the towing plane.

It is a further object of the invention to provide a towed target orglider of the above type having self-contained mechanism forautomatically controlling the movement of the glider between its in-lineand offset positions; and more specifically to provide mechanism whichis responsive to the speed at which the glider is towed to control itsposition relative to the line of flight of the towing plane.

Other objects of the invention are the provision of a towed glider whichin its configuration generally resembles the conventional airplane andone which has simple and reliable control mechanism completely housedwithin the fuselage of the glider for shifting the glider between itsdifferent flight positions.

These and other objects and advantages ol the invention will becomeevident from the following detailed description of one embodiment of theinvention shown in the accompanying drawings.

In these drawings: 1

Fig. 1 is a perspective view of a towed winged glider embodying theinvention shown in offset position relative to the line of flight of thetowing plane;

Fig. 2 is a partial front view of the target shown in Fig. 1;

Fig. 3 is a transverse section through the nose of the target taken onlines 3-3 of Fig. 4 and looking forward in the direction of the arrows;

Fig. 4 is a View looking at one of the tow bar assemblies, the fuselagebeing shown in section on line 4-G of Fig. 2; and

Fig. 5 is a diagrammatic showing of the circuit connections for thereversible electric motor and the control switches therefor.

As herein shown, the towed glider generally indicated in Fig. 1 by thenumeral It comprises a long cylindrical fuselage l2 supporting two wingsM and I6 located substantially midway between the fore and aft ends ofthe fuselage, two tail surfaces I8 and 20 located at the extreme aft endof the fuselage and two tow bar assemblies 22 and 24 located at theextreme forward end of the fuselage.

Each wing panel comprises a leading edge assembly 26 and a trailing edgeassembly 28 which are detachably secured together by piano hinges. Theentire wing assembly is interchangeable, left and right, and is fastenedto the fuselage by bolts, not shown, so that in service a damaged wingmay be quickly repaired by a standard wing part.

The tail surfaces I8 and 20 are similar in construction to the wing,comprising leading edge assemblies 30 and trailing edge assemblies 32connected by piano hinges. Each tail surface l8 and 20 is detachablybolted to the fuselage and these surfaces, like the wings, areinterchangeable left and right. It will .be noted from Fig. 1 that thewings l4 and I8 have a slight dihedral angle while the tail surfaces [8and 20 and the tow assemblies 22 and 24 are disposed at very sharpdihedral angles of approximately 32. An

empennage of horizontal and Vertical surfaces familiar to those skilledin the art of aircraft may be employed as an alternate for the V-typetail surfaces shown.

The tow bar assemblies 22 and 24 are carried by a fuselage nose section34 best shown in Fig. 4 and comprise identical tubular tow posts, orbars, 36, the inboard ends of which have fittings 38 secured rigidly ina solid nose portion 40. Each of these tow b-ars has an outboard andfitting, or cap, 42 of streamlined cross section extending fore and aftthereof. These outboard fittings are supported by tension cables 44(Fig. 2) extending inboard and aft therefrom to the fuselage nosesection 34 for the purpose of supporting the tow bars against bendingmoments caused by the tow cable and by the trailing control surfaces 45,46 carried by the tow bars. For target glider use, the fuselage nosesection 34, housing the offset position operative mechanism, may be madeof cast iron as a protection for the mechanism agaisnt the bullets firedat the target.

The trailing control surfaces 45, 46 are supported by piano hinges, theforward hinge strips c1 of which are secured to the tow bars 35 substantially along the entire length thereof, as by rivets 48, and therear hinge strips 49 of which are secured to the lower surface of thecontrol surfaces 45, 46 at the leading edge thereof. These piano hingesare similar to those previously mentioned in connection with the wingand tail surface assemblies.

The target is adapted to be towed behind the towing plane by means of aV-bridle 52 trailing behind a tow cable 54 suitably attached to thetowing plane. The ends of the bridle 52 pass through cable sheaves 55supported in brackets 58 on the forward ends of fittings l2 and thenpass through transverse conduits 52 which are supported on the leadingedges of the tow bars 36 by clips 54. These cable ends are attached tothe opposite ends of a chain 68 which passes beneath a central sprocket68 mounted in the rigid portion 48 of the fuselage nose in the centrallongitudinal plane of the fuselage. The sprocket 68 is driven by areversible electric motor 7B which, through the action of the sprocket68 on the chain 56, offsets the bridle 52 from a symmetrical positionthereof relative to the tow bars 22 and 24, in which the vertex 53 ofthe bridge 52 and the towing cable as he in the symmetrical axis T2parallel to the longitudinal axis of the glider I8, into an offsetposition such as shown in Fig. 1. It will be understood that, while Fig.1 shows the glider being towed in an offset position at an angle Of 35to the line of flight of the towing airplane, the angle of the offsettow position may be varied in some installations or may be pre-set bylimiting the travel movement of control surfaces 45, 45.

The control surfaces 45, 46 on the tow bars are also simultaneouslyoperated by the same electric motor 75. To this end the motor I has apinion gear which meshes with a sector gear 75 rotatable about a pivotpin I8 suitably supported in the nose structure as by the clip 85 andfixed bar I32. A control surface actuating arm 85 which is also pivotedon the pivot pin I8 and is fixed to the sector gear I5 by rivets 86extends through a slot 88 in the nose fitting 35. The free end ofactuating arm 86 is pivotally connected at 90 to oppositely directedcontrol surface actuating links 92 and 94 by means links 96 and. 98. Thelinks 92 and 95 are pivotally connected at their outboard endsrespectively by links 99 and 99a to the inboard ends of the swivel studsI05 and I02 which extend through the control surfaces 45, 45. Theconnection between the arm 84 and the control surfaces is such that, bylateral movement of the arm about its pivot 78 from the full lineposition into the dotted position shown in Fig. 3, the control surfaceson the tow bars will be operated into the Fig. 2 position in which theport surface (shown as the right hand surface 45 in Fig. 2) is deflectedoutboard and downwardly and the starboard surface (shown as the surface45 in Fig. 2) left hand is deflected inboard and upwardly. The abovedescribed movement of the control surfaces will result in the gliderassuming an offset position to starboard but by providing for theopposite movement of the surfaces, an offset position to port may beobtained. In the position of the parts of the control surface assemblyshown in Fig. 3 the two control surfaces 45, 46 are both in theirneutral, 0r undeflected, positions.

The control arm 84 in its vertical position shown in Fig. 3 is alsoadapted to engage the operating member I54 of a normally closed electriclimit switch A, which is supported on a bracket I06 of the fixed nosestructure, and hold this switch in its contact open position. A similarelectric limit switch B is mounted on bracket I58 on the fixed nosestructure in position to be engaged by arm 84 in the other extremeposition of this arm shown dotted in Fig. 3 in which position of arm 84the operating member IIB of the switch 13 is depressed into contact openposition. The switches A and B, which are shown diagrammatically in Fig.5, are identical, the switch A comprising stationary contacts H2 andmovable contact bridging member iI- which is constantly biased intoengagement with the stationary contacts M2 by compression spring H6.Switch 3 comprises the stationary contacts II8, a cooperating movablecontact bridging member I 23 and a compression spring I22 whichconstantly biases the bridging member I25 into engagement with thestationary contacts I !8.

The motor control circuit shown in Fig. 5 also includes a third switch Cwhich is a double throw starting switch including an operating memberI25 and a movable contact bridging member I28 adapted to bridge twospaced sets of stationary contacts I28 and i38 a compression spring I32being provided to normally maintain the bridging member in engagementwith the stationary contacts 28.

The switch C is supported on the fixed nose structure 34 by a suitablebracket I35 with its operating member I24 beneath the hinged bracket 13%of a drag flap 133 which is pivoted at M5 on the fixed nose structure34. The hinged bracket I 35 has an ear M2 extending forwardly of itspivot I50 and a compression spring I54 is provided between this car anda pad M3 on the nose structure for constantly biasing the flap I38 intothe elevated position shown in Fig, 4 in which it projects above thestreamlined surface of the fuselage !2 into the airstrearn. It will beevident from Fig. 4 that whenever a sufficient force is exerted on thedrag flap I 38 by the airstream this flap will be moved against theaction of the spring Mil partially into a recess I48 in the fuselageskin. The flap will not be depressed to a position where it will beentirely flush with the fuselage skin for, in that position, it wouldlose its air loading. It will also be evident that in the flush positionof the flap I38 the end portion I58 of the bracket I35 will have engagedand depressed the operating member 925 of switch C into its lowermostposition in which it bridges the contacts I 39.

As shown in Fig. 5 the reversible motor in has two sets of terminals 252and IE5. The terminals I 52' are connected to the negative terminal ofthe battery I56 by conductors I58 and i 50 respectively while theterminals I54 are connected through parallel conductors I62 and I64 withthe positive terminal of the battery. From Fig. 5 it will be noted thatthe contacts H2 of the limit switch A are connected in conductor I52while the similar contacts H8 of limit switch 3 are comiccted inconductor I54. Also the double throw switch C has its stationarycontacts I28 connected in conductor IE2 and its contacts I36 connectedin conductor I54. These circuit connections are such that uponcompleting the circuit through conductor I62 the motor ID will rotate inone direction, whereas completion of the circuit through conductor I64will result in its rotation in the opposite direction.

The towed glider is provided with a main land'- ing gear comprisingwheels I66 and cantilever leaf springs I68 and with a nose skid I10 bestshown in Figs. 2 and 4.

In operation the glider may be launched by a "snatch pick-up or by adrag take-01f as desired. In either case upon take-oif the parts will bein the positions shown in Figs. 3, 4 and 5 in which the control arm 84is engaging operating member I04 of limit switch A and holding it open,the drag flap I38 is in raised position and the bridging member I36 ofswitch C is bridging contacts I28. Limit switch B is closed butconductor I64 is open at contacts I30 of starting switch C. Also, thecontrol arm 84 being in its vertical position shown in Fig. 3, thecontrol surfaces 45, 46 on the tow bars are in their neutral,undeflected positions and the chain 66 is in a position on the sprocket88 such that the two branches of the V-bridle 52 between the point 53and the cable sheaves 58 are of equal length. Accordingly, the gliderwill, during the take-off, be directly in line with the towing plane inthe usual manner and it will continue to maintain this in-line positionuntil the relative airspeed is reached at which the flap I38 isdepressed, by the air loads acting thereon, to a position sufiicient tooperate the control surface actuating mechanism.

The movement of the glider to offset position is controlled by the pilotof the towing plane by controlling the speed at which the glider istowed, the critical speed at which ofisetting of the glider takes placebeing determined by the choice of spring I44. Below the selectedcritical speed, which may be by way of example a speed of 150 miles anhour, the drag flap I38 will remain in the elevated position shown inFig. 4, but when the predetermined speed has been reached this flap willbe depressed to move the bridging member l26 of starting switch C out ofengagement with contacts I28 and into engagement with contacts I3fi.Closing of contacts I30 will result in completing the circuit frombattery I56 through conductor I64, switch C at contacts I30, switch B atcontacts H8 to one of the motor terminals I54 and from the correspondingterminal I52 through conductor M0 to the negative terminal of thebattery. The motor will operate to move the chain 56 so that one branchof the V-bridle will be shortened and the other lengthened until point53 of the bridle has been displaced into the offset position shown inFig. 1. Simultaneously the gear 14 of the motor will have moved thesector gear 1'6 and its attached arm 34 into the dotted position of thelatter shown in Fig. 3 in which it engages the operating member I Ill oflimit switch B, resulting in the opening of the circuit above traced andthe de-energization of the motor.

As long as the pilot flies the glider above the selected critical speedthe starting switch C will remain with its movable contact member lZEbridging contacts 30 and, since the conductor I62 is now open at switchC and the conductor I64 is open at switch 13, the parts will remain. inthis position. When it is desired to resume inline flight conditions tomake a landing the pilot merely reduces his speed and consequently thespeed of the glider below the critical speed, allowing the drag flap I38to rise and close the motor circuit through conductor I62 at contactsI28 of switch C, whereupon the motor will run in the reverse directionand return the parts to their original positions.

It will be evident that as a result of this invention a towed target hasbeen provided which generally simulates an airplane in appearance andflight characteristics and which is capable of being towed at highspeed. Further, automatically operative mechanism has been provided fortakeoff and landing of the target in an in-line position relative to thetowing plane while permitting offset flight of the target during targetpractice. Similarly, it is evident that, with the invention described,two or more gliders, such as cargo gliders, may be towed insubstantially in-line or only slightly offset positions during take-offor early flight and landing and that operative mechanism has beenprovided to have the gliders assume a greater offset position relativeto the line of flight of the towing airplane during higher speed.

The advantages of offset towing of the glider when it is used as atarget will, it is believed, be obvious since it permits the simulationof actual combat involving attack from the front and rear of the targetby fighter planes without endangering the towing plane and its pilot whowould otherwise be in the line of fire.

It will further be evident that by this invention a particularly simpleand effective mechanism has been provided by which the pilot of thetowing airplane can control the movement of the towed glider betweenin-line and offset positions, yet does not require any control apparatuswhich is not wholly contained in the glider.

While only one embodiment of the invention has been illustrated anddescribed it will be evident that numerous changes in the constructionand arrangement of the parts may be made without departing from thescope of the appended claims.

What it is desired to secure by Letters Patent is:

1. A glider adapted to be towed by a powered airplane, a movable controlsurface on said glider, and means governed by the speed of said gliderfor moving said control surface to shift said glider from an in-lineposition to an offset position relative to the line of flight of thetowing airplane.

2. A glider adapted to be towed by a powered airplane, means carried bysaid glider for shifting the latter between an in-line position and anoffset position relative to the line of flight of the towing airplane,and means governed by the speed of said glider for controlling saidshifting means.

3. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, andmeans governed by the speed of said glider for shifting said glider froman in-line position to an offset position relative to the line of flightof the towing airplane including means for controlling the de-- flectionof said surfaces.

4. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces andmeans governed by the speed of said glider for shifting said glider froman in-line position to an offset position relative to the line of flightof the towing airplane including means for moving said surfaces betweena neutral position and a deflected position thereof.

5. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, andmeans governed by the speed of said glider for shifting said glider froman in-line position to an offset position relative to the line of flightof the towing airplane including means for simultaneously shifting saidtow cable connection and moving said control surfaces.

6. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, andmeans for shifting said glider between an in-line position and an offsetposition relative to the line of flight of the towing airplane includingpower perated means carried by said glider for simultaneously laterallyshifting said tow cable connection and for deflecting said controlsurfaces.

7. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, andmeans for shifting said glider between an in-line posi tion and anoffset position relative to the line of flight of the towing airplaneincluding power operated means controlled by the pilot in the towingairplane for simultaneously deflecting said surfaces and laterallyshifting said tow cable connection, said power operated means includinga drag flap carried by said glider and controlling said glider shiftingmeans.

8. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, andmeans for shifting said glider between an in-line position and an offsetposition relative to the line of flight of the towing airplane includingpower operated means for simultaneously laterally shifting said towcable connection and for operating said control surfaces, said poweroperated means including a motor, a source of motive power, controllingmechanism therefor, and means including a drag flap governing theoperation of said controlling mechanism.

9. A glider adapted to be towed by a powered airplane and including afuselage, wing and tail surfaces supported by said fuselage, a tow cableconnection to said glider forward of said wing surfaces, pivotallysupported trailing control surfaces adjacent the forward end of saidfuselage, means for shifting said glider between an in-line position andan offset position relative to the line of flight of the towing airplaneincluding a drag flap on said glider, and means operated by said flapfor simultaneously laterally shifting said tow cable connection relativeto said glider and for operating said control surfaces.

10. A glider adapted to be towed by a powered airplane and including afuselage, sustaining surfaces supported by said fuselage intermediatethe ends thereof, bridle posts carried by the forward portion of saidfuselage, control surfaces pivotally mounted on trailing edges of saidbridle posts, tow cable connections including a V-bridle carried by saidposts and a common operating means fpr effecting lateral displacement ofthe vertex of said V-bridle and for eifecting deflection of saidsurfaces.

11. A glider adapted to be towed by a powered airplane and including afuselage, sustaining surfaces supported by said fuselage intermediatethe ends thereof, bridle posts carried by the forward portion of saidfuselage, control surfaces pivotally mounted on trailing edges of saidbridle posts, tow cable connections including a V-bridle carried by saidposts, and a common operating means for effecting lateral displacementof the vertex of said V-bridle and for effecting deflection of saidsurfaces, and speed responsive means for controlling said operatingmeans.

12. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of movable control surfacesmovable between a neutral position and a de- 8 flected position forshifting said glider from an in-line position to an offset positionrelative to the line of flight of the towing airplane, and meansincluding a pivoted drag flap responsive to the speed of said glider forcontrolling the movement of said surfaces.

13. A towed glider including a fuselage, sustaining surfaces supportedby said fuselage intermediate the ends thereof, bridle posts carried bythe forward portion of said fuselage, control surfaces pivotally mountedon the trailing edges of said bridle posts, a V-bridle having its vertexnormally disposed in the line of flight of the glider, means carried bythe glider for shortening one leg of said bridle and lengthening theother, whereby to permit said glider to fly in an offset positionrelative to the line of flight of the towing airplane, and meansgoverned by the speed of the glider for controlling the operation ofsaid first mentioned means.

14. A towed glider including a fuselage, main sustaining surfacessupported by said fuselage intermediate the ends thereof, bridle postscarried by the forward portion of said fuselage, control surfacespivotally mounted on the trailing edges of said bridle posts, a V-bridleconnected to said posts, means for shifting said target between anin-line position and an offset position relative to the line of flightof the towing airplane including mechanism for changing the relativelength of the arms of said V-bridle, and means for operating saidsurfaces.

15. A towed glider including a fuselage, main sustaining surfacessupported by said fuselage intermediate the ends thereof, bridle postscarried by the forward portion of said fuselage, control surfacespivotally mounted on the trailing edges of said bridle posts, a V-bridleconnected to said posts, means for shifting said glider between anin-line position and an offset position relative to the line of flightof the towing airplane including mechanism for changing the relativelengths of the arms of said V-bridle and means for operating saidsurfaces, and means governed by the speed of the glider for controllingsaid shifting means.

16. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, a dragflap carried by said glider, and means for shifting said glider betweenan in-line position and an offset position relative to the line offlight of the towing airplane including means governed by said drag flapfor simultaneously shifting said tow cable connection and moving saidcontrol surfaces while maintaining unaltered the line of flight of thepowered airplane.

17. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, asource of power in the glider, control means carried by the towingairplane and means for shifting said glider between an in-line positionand an offset position relative to the line of flight of the towingairplane including power operated means carried by said glider andgoverned by said control means for simultaneously laterally shiftingsaid tow cable connection and for deflecting said control surfaces whilemaintaining the original line of flight of the powered airplane.

18. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, andmeans for shifting said glider between an in-line position and an offsetposition relative to the line of flight of the towing airplane includingpower operated means controlled by the pilot in the towing airplane forsimultaneously deflecting said surfaces and laterally shifting said towcable connection, said power operated means including a drag flapcarried by said glider and controlling said glider shifting means whilemaintaining the original line of flight of the powered airplane.

19. A glider adapted to be towed by a powered airplane and including atow cable connection to said glider, a pair of control surfaces, andmeans for shifting said glider between an in-line position and an offsetposition relative to the line of flight of the towing airplane includingpower operated means for simulaneously laterally shifting aid tow cableconnection for operating said REFERENCES CITED The following referencesare of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,373,236 Eflinger Apr. 10, 19452,400,400 Duer May 14, 1946

